1. Field of the Invention
The invention relates to a color wheel and more particularly, this invention relates to a color wheel, which is used in the projection technology.
2. Description of the Related Art
Digital Light Processing (DLP) is a widely used projection technology. DLP has several advantages over other methods including high brightness, accurate tone reproduction, fast response time, noise-free operation, and thin and light composition.
In a DLP projector, a digital control method and a reflection principle are adopted. Light rays from the light source are collected and focused by the lens to pass through three color filters. Then, the light rays are projected onto a digital micro-mirror device (DMD). Since the DMD includes several movable micro mirrors, driving electrodes may control the tilt angle and deflection time of each movable mirror. Then, the light rays are projected to form an image by switching the direction of the light ray reflections.
In the DLP projector, a color wheel 2 for generating the light rays of several colors is generally provided. Referring to FIG. 1, the color wheel 2 mainly includes a washer 21, a color filter 22 and a motor 23. The washer 21 and the color filter 22 are mounted on the motor 23. In this case, the motor 23 includes a housing 231 and a motor body 232, which rotates together with the housing 231.
In addition, the color wheel is also used in Liquid Crystal on Silicon (LCOS) projectors and Liquid Crystal Display (LCD) projectors. Herein, the function of the color wheel is the same as in DLP projectors for separating the light rays into several colors.
In general, the motor for the color wheel rotates at a speed higher than 7200 rpm. When the rotation center of the motor is away from the central axis of the rotation shaft (i.e., when the rotation center is not located on the central axis of the rotation shaft), the operation of the color wheel may be adversely influenced by vibration and noise. Further, the operational reliability of the color wheel may decrease.
It is therefore an important objective of the invention to provide a color wheel to solve the problem mentioned above.